Shielded ultra high frequency cathode-ray tube



Nov. 21, 1950 s. J. KOCH ET AL SHIELDED ULTRA HIGH FREQUENCY CATHODE-RAY TUBE Filed Sept. 11. 1947 IN VEN TOR.

Patented Nov. 21, 1950 SHIELDED ULTRA HIGH FREQUENCY CATHODE-KAY TUBE Stanley-J. Koch, Clifton, and Robert E. Rutherford, Nutley, N; 3., assignors to Allen B. Du Mont Laboratories, Inc., Passaic, N. J., a cor.- noration of Delaware Application September 11,1947, Serial No. 77.3 448 Claims.

This invention relates to a cathode-ray tube a which has pairs of deflection plates so located that they are particularly well shielded from outside disturbances. The plates are mounted on conductors which are shielded where they are inside of the cathode-ray tube.

With this invention a completely shielded deflection plate system for a cathode-ray tube is provided. This is especially important when measurements at ultra-high frequencies are to be made. By this invention, a coaxial line may be attached directly to the deflection plates by means of short lengths of coaxial line sealed into the sidewall of the tube, these lines consisting of a tubular outer member which connects to to outer member of the coaxial cable outside the tube, and to a common shield around the deflecting plates within the tube. A short length of rod sealed to a glass button comprises the inner member, with a deflection plate welded to its inner end.

The invention may be understood from the description in connection with the accompanying drawing in which:

Fig. 1 is a plan view of the deflection plate structure, showing the neck of the tube in section.

Fig. 2 is a side view partly in section and Fig. 3 is a side view at right angles to Fig. 1.

In the drawings, reference character l indicates the glass neck of the tube into which the deflecting plate structure is sealed.

Radially extending short lengths of metal tubing 2 have sma l glass buttons 3 sealed therein. A radially extending conductor 4 is an chored in each button 3. The outer end of each conductor 4 is adapted to be received by the central conductor of a coaxial cable fitting. The other end of each conductor 4 supports a beam deflecting plate 5. Each assembly 2, 3, l constitutes a short section of a coaxial line.

An internally threaded ring 6 of metal is anchored in each tubing 2. These rings are adapted to receive the external portions of coaxial cable fittings, and are in good electrical contact with tubes 2. The outer end of each tube 2 is sealed to the glass neck I as indicated at 2'. This sealing may be done, for example, by fusing.

The inner end of each tube 2 is welded as indicated at 6 to a supporting frame I which is attached to supporting rods 8, which in turn are supported by the electron gun assembly of the tube (not shown) and connected electrically to the second anode of said assembly.

An upper shield ring 9 and a lower shield ring ID, that are provided with central holes for the electron beam are also attached by welding, for example, to the supporting frame 1.

This supporting frame is made up of a square metal plate with two of its opposite edges la. bentupat right angles and its other edges 1b bent down at right angles to the plate I. The ends of these bent up and bent down portions are bent outwardly at right angles and spot welded to the shield rings 9 and II], respectively. ring ll of glass is fused onto the outside of each tube 2, encircling the area where the glass button 3 is sealed to the inside. This glass has substantially the same coefficient of expansion as the glass of the button 3.

What is claimed is:

l. A cathode-ray tube having a deflection system comprising two pairs of shielded deflection plates, means to connect said deflection plates respectively to the inner ends of the central conductors of short lengths of coaxial lines that lead to said plates, the inner ends of the outer conductors of said coaxial lines being connected to and supported by a supporting frame located on the axis of said tube, the outer ends of the outer conductors of said coaxial lines being sealed to the wall of said tube and adapted to receive a coaxial connector fitting.

2. The device of claim 1 in which said supporting frame is provided with a shield ring having an aperture located on the axis of the tube to permit passage of the electron beam.

3. The device of claim 1 in which means are provided to connect a plurality of said coaxial lines to said deflecting system.

4. The device of claim 1 in which said short lengths of coaxial lines consist of an outer conductor of thin-wall tubing and an inner conductor sup orted by and sealed to a small glass b tton sealed to the inside of said outer conductor.

5. A shielded deflection system for a cathoderay tube adapted to have coaxial cables connected thereto, which comprises four metal tubes each anchored at right an les to two others in the neck of said cathode-ray tube, threaded rings in said metal tubes for the outer leads of said cabes and insu ating sup orts in said metal tubes for the center leads of said cables.

6. The system of claim 5 in which metal discs on opposite sides of said deflection system are provided to constitute a portion of the shield of said shielded system.

7. The system of claim 5 in which metal discs on opposite sides of said deflection system are provided to constitute a portion of the shield of said shielded system, said metal discs being provided with axially aligned apertures to permit passage of the electron beam of said cathode-ray tube.

8. A shielded deflection system for a cathoderay tube adapted to have coaxial cables connected thereto, which comprises four metal tubes each at right angles to two others in the neck of said cathode-ray tube, threaded rings in said metal tubes for the outer leads of said cables and insulating supports in said metal tubes for the center leads of said cables and deflection plates supported by said center leads.

9. A cathode ray tube having a plurality of defiection plates, a plurality of coaxial leads, said deflection plates being connected respectively to the inner ends of the inner conductors of said co-laxial leads, the outer ends of the outer conductors of said coaxial leads being sealed respectively to the wall of said tube and adapted to receive a coaxial connector fitting, the inner ends therein and having portions extending at right angles to said plate in one direction and alternate portions extending at right angles in the other direction, said portions extending longitudinally of said tube adjacent said plates, said outer conductors being connected respectively to said portions and said inner conductors extending respectively therethrough.

10. The apparatus of claim 9 including a saucer shaped shield of conducting material connected to and extending laterally across the open ends Of said portions, said saucer shaped shield having a central aperture therein in alignment with said deflection plates and the axis of said tube. i

STANLEY J. KOCH. ROBERT E. RUTHERFORD.

REFERENCES CITED The following references are of record in the me of this patent:

UNITED STATES PATENTS Number Name Date '25 2,381,539 Hartley Aug. 7, 1 945 2,442,545 Koch et al June 1, 1948 

